More than 1.3 billion people live on our planet’s coasts, most of them in developing countries. Put another way, one fifth of our species live within one hundred kilometers of a coastline. Those people, by and large, depend on coastal seas not just for food, but also for their livelihoods. And, as we all know, those coastlines are under increasing risk not just from climate change but also from overpopulation, and from the interaction between the two processes. Together, those threats will increase the pressure on tropical coastal waters, making the seas increasingly unable to meet the demand our species requires of it.

The main problem, according to 24 scientists from Canada, the USA, the UK, China, Australia, New Caledonia, Sweden, and Kenya, writing in the journal Marine Pollution Bulletin, is that most of those coastal regions are “lacking…holistic, regional-scale management approaches to balance the growth in competing demands from fisheries, aquaculture, shipping, oil, gas and mineral extraction, energy production, residential development, tourism and conservation.” The approaches to sustainable management that do exist, they argue, are too piecemeal, and suffer from weak governance, corruption, and the persistent belief that the ocean is a place of unlimited bounty. In addition, they tend to be geographically limited in scope, or focus to narrowly on single issues, such as conservation or fishing, while ignoring others, such as tourism and aquaculture.

The researchers offer a series of recommendations for better collectively managing our coastal resources, both at small and large scales. They argue that zones be developed according to the following purposes: ports and shipping, aquaculture, small-scale fisheries, tourism, and biodiversity conservation. For example they say that wharfs and breakwaters should be constructed with greater complexity to provide more shelters for fish, which are often abundant in ports. That achieves gains in conservation without reducing the efficiency of shipping or tourism operations. They argue, predictably, that shipping routes shouldn’t overlap with fishing grounds or with wildlife protection spaces. They suggest that leasing systems be established to create incentives for aquaculture, but that aquaculture sites be distributed to avoid depleting waters of oxygen. Further, they recommend targeting species for aquaculture that can survive or thrive in warmer conditions (and who don’t pose a threat as invasive species) or developing aquaculture systems that can operate in deeper, cooler waters.

It’s a tall order, to be sure, and the researchers acknowledge as much. Meeting the demands of growing populations in a warming world will require “effective adaptation to local societal, cultural and governance traditions, effective and sustained participation of all community groups, strong local and national political leadership, and vigorous support by development partners and NGOs. Urgent global efforts to reduce [greenhouse gas] emissions are also needed,” they write.

The alternative, of course, is dire. Coastal fisheries will collapse. Reefs will die, which will also affect food security. Pollution will deplete coastal waters of oxygen and toxic algal blooms will become a permanent part of the landscape. Coastal development, combined with severe weather and rising seas, will erode natural coastlines, which will further impact conservation, fisheries, and shipping. Efforts to mitigate these problems in the future will be far more costly than they are now, which will itself further strain coastal communities. Still, “humanity has the capacity to substantially improve coastal management,” the researchers offer, with a glimmer of hope. “The futures of millions of poor people living on tropical coasts depend on us collectively rising to that challenge.” Can we do it? – Jason G. Goldman | 04 July 2014